Communication antennas, including communications antennas for vehicles, are generally adapted to receive and/or transmit and receive signals in a particular frequency range. The antennas are sized and configured in order to optimize efficiency at particular frequency ranges.
VHF, UHF and satellite antennas have conventionally been implemented in separate antenna structures. For example, receiving satellite antennas have generally been implemented with a dish type antenna structure while VHF and UHF antennas have generally been implemented as monopole or dipole antennas and sometimes as dipole array structures. UHF antennas have also been implemented as dish antennas. To miniaturize the size of antennas, meander line loaded antennas are known and are exemplified by U.S. Pat. Nos. 5,790,080; 6,323,814; 6,373,440; 6,373,446; 6,480,158; 6,492,953; 6,404,391 and 6,590,593, assigned to the assignee hereof and incorporated herein by reference. However, notwithstanding various antenna design techniques, conventional, VHF and UHF and satellite antennas have generally not been combined into a single antenna structure.
For example, military, law enforcement and even commercial vehicles may be required to be equipped with communications devices to permit operators to exchange information with a variety of different information services, command and control or dispatch centers, GPS and other information. Therefore, it is not uncommon for such vehicles to include multiple, separate antennas, each designed to communicate efficiently at a particular frequency range or a few frequency ranges.
There is a need, however, for an antenna that is capable of transmitting in the VHF, UHF and satellite frequency ranges using a shared radiating element. There is a further need for a combined antenna to assume a standard footprint, such as a co-axial whip antenna, that may be implemented and fitted onto existing vehicles. There is still a further need for a combined antenna capable of efficient operation in the following four frequency bands: 30-88 MHz, 108-156 MHz, 225-450 MHz and 1350-1550 and 1650-1850 MHz that fits into the form factor of a 30-88 MHz whip antenna.